Patrick Mcnally

Patrick Mcnally
Dublin City University | DCU · School of Electronic Engineering

PhD, Brown University, RI, USA

About

257
Publications
32,826
Reads
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1,775
Citations
Citations since 2017
31 Research Items
699 Citations
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2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
Introduction
Patrick McNally is a Full Professor in the School of Electronic Engineering, Dublin City University. Patrick does research in Electronic Engineering, Engineering Physics and Materials Engineering. Current research interests include radio emission spectroscopy techniques for plasma process monitoring, x-ray diffraction imaging technology, and copper halide materials and device development.
Additional affiliations
October 1991 - present
Dublin City University
Position
  • Professor

Publications

Publications (257)
Article
Calcium carbonate (CaCO3) is considered an ideal candidate for large scale energy storage systems due to its high energy density, high operating temperature and low cost. Its degrading performance over consecutive energy storage/release cycles is the main inhibiting factor from utilising such material as a high-temperature thermal battery for conce...
Article
Full-text available
In this report, a novel non-contact, non-invasive methodology for near and quasi real-time measurement of the structuring of metal surfaces using pulsed laser ablation is described. This methodology is based on the use of a multi-messenger data approach using data from Optical Emission Spectroscopy (OES) and Radio Emission Spectroscopy (RES) in par...
Article
Full-text available
X-ray diffraction imaging was used to monitor the local strains that developed around individual n–p–n bipolar transistors within fully encapsulated packages under conditions of extremely high forward bias to simulate accelerated ageing. Die warpage associated with the packaging was observed to relax systematically as the polymer became viscous due...
Article
Functionally grading material composition in laser-powder bed fusion grants the potential for manufacturing complex components with tailored properties. The challenge in achieving this is that the current laser-powder bed fusion machine technology is designed to process only powdered feedstock materials. This study presents a multi-feedstock materi...
Article
Laser-powder bed fusion was identified as a promising technique for manufacturing metal matrix composites. However, over a decade later, little progress has been made in addressing the persisting issues hindering the wider exploitation and industrial usage of metal matrix composites. Therefore, the present study proposes the implementation of a fea...
Article
Despite the accelerated growth of laser-powder bed fusion in recent years, there are still major obstacles to be overcome before the technology enjoys truly widespread adoption. These include inconsistent part quality and repeatability issues linked to variability in the properties of printed parts. Commonly, the print location across the build pla...
Article
Full-text available
It is challenging to crystalize a thin film of higher melting temperature when deposited on a substrate with comparatively lower melting point. Trading such disparities in thermal properties between a thin film and its substrate can significantly impede material processing. We report a novel solid-state crystallization process for annealing of high...
Article
The study of growth kinetics of graphene on Polyimide upon carbon-dioxide (CO2) laser irradiation enables optimisation of crystal size for maximum electrical conductivity. We report the first study on growth kinetics of graphene produced by laser carbonization of polyimide using the Arrhenius equation. The peak irradiation temperature (Tirr) for ea...
Preprint
Full-text available
We demonstrate that a passive non-contact diagnostic technique, radio emission spectroscopy (RES), provides a sensitive monitor of currents in a low pressure radio frequency (RF) plasma. A near field magnetic loop antenna was used to capture RF emissions from the plasma without perturbing it. The analysis was implemented for a capacitively coupled...
Article
Additively Manufactured (AM) titanium (Ti) components are routinely post-thermal heat treated (HT), to reduce internal stresses, as well as to obtain more desirable microstructural features, yielding improved mechanical performance. Currently, there is no consensus on the optimum HT method for AM Ti-6Al-4V, as the mechanism for the main phase trans...
Article
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We describe a novel solid state crystallisation method for optimising a thin film transparent conductive oxide when deposited on flexible polymer substrates. The method is based on ultra-short non-thermal laser sintering of indium tin oxide (ITO) thin films. In this study, we used commercial ITO thin films deposited on a flexible polyethylene terep...
Article
Full-text available
Process monitoring and sensing is widely used across many industries for quality assurance, and for increasing machine uptime and reliability. Though still in the emergent stages, process monitoring is beginning to see strong adoption in the additive manufacturing community through the use of process sensors recording a wide range of optical, acous...
Article
Full-text available
We propose a novel low temperature annealing method for selective crystallization of gold thin films. Our method is based on a non-melt process using highly overlapped ultrashort laser pulses at a fluence below the damage threshold. Three different wavelengths of a femtosecond laser with the fundamental (1030 nm), second (515 nm) and third (343 nm)...
Article
Full-text available
X-ray diffraction imaging (XRDI) (topography) measurements of silicon die warpage within fully packaged commercial quad-flat no-lead devices are described. Using synchrotron radiation, it has been shown that the tilt of the lattice planes in the Analog Devices AD9253 die initially falls, but after 100 °C, it rises again. The twist across the die wa...
Article
Full-text available
Additive manufacturing is being increasingly used in the fabrication of Ti-6Al-4V parts to combine excellent mechanical properties and biocompatibility with high precision. Unfortunately, due to the build-up of thermal residual stresses and the formation of martensitic structure across a wide range of typical processing conditions, it is generally...
Article
Full-text available
In this work, a gas atomised stainless steel AISI 316L powder was used as metal matrix and SiC was employed as a nano reinforcement. The powders were experimentally characterised to determine the effect of the morphology, size, and levels of reinforcement on the powder flowability. The powder was developed via the powder metallurgy route and the ef...
Article
Full-text available
The application of X-ray Diffraction Imaging to measure in operando thermal strains at individually powered components within fully packaged LM3046 silicon devices is described. It is shown that as the local strains increase with power dissipated, above a threshold power loading, the associated region of enhanced X-ray intensity increases monotonic...
Article
During 4H silicon carbide (4H-SiC) homoepitaxy and post-growth processes, the development of stress relaxation has been observed, in which interfacial dislocations (IDs) are formed at the epilayer/substrate interface, relaxing the misfit strain induced by the nitrogen doping concentration difference between the epilayer and substrate. It is widely...
Article
We present in-situ observations of the dynamical operation of multiple double-ended Frank-Read dislocation sources in a PVT-grown 4H-SiC wafer under thermal gradient stresses. The nucleation of these sources is facilitated by a specific configuration consisting of one basal plane dislocation (BPD) segment pinned by two threading edge dislocations (...
Article
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The crack geometry and associated strain field around Berkovich and Vickers indents on silicon have been studied by X-ray diffraction imaging and micro-Raman spectroscopy scanning. The techniques are complementary; the Raman data come from within a few micrometres of the indentation, whereas the X-ray image probes the strain field at a distance of...
Preprint
Full-text available
The crack geometry and associated strain field around Berkovich and Vickers indents on silicon have been studied by X-ray diffraction imaging and micro-Raman spectroscopy scanning. The techniques are complementary, the Raman data coming from within a few micrometers of the indentation, whereas the X-ray image probes the strain field at a distance o...
Article
Full-text available
Highly efficient transparent blue emitters have been pursued for many years, driven in large part by solid-state lighting technology, and the need for blue/UV spectroscopic sources. CuBr is a strong candidate material, chiefly due to its relatively large excitonic binding energies. However, the semiconductor copper halides (CuCl, CuBr, CuI) have be...
Article
Full-text available
A novel approach to remotely monitor low pressure non-equilibrium plasmas is reported. A magnetic field antenna is positioned in the near field of a capacitively coupled plasma. Magnetic flux from plasma currents, present near the viewport, is intercepted by a calibrated loop antenna placed outside the chamber. The induced signal current is correla...
Article
The ability to measure intrinsic thermal conductivity via a non-contact, non-destructive process is extremely attractive. Micro-Raman spectroscopy has been demonstrated to enable effective non-contact thermometry with further work providing a non-destructive estimation of values for thermal conductivity on suitable materials. However significant li...
Conference Paper
Full-text available
We have recently shown that x-ray synchrotron-based B-Spline X-Ray Diffraction Imaging (B-XRDI), and laboratory-based X-Ray Diffraction (XRD) techniques, can be used to non-destructively and in situ evaluate die warpage and strain inside fully encapsulated chip packages. In this paper, we show that both synchrotron-based X-Ray Diffraction Imaging (...
Conference Paper
We have recently shown that x-ray synchrotron-based B-Spline X-Ray Diffraction Imaging (B-XRDI), and laboratory-based X-Ray Diffraction (XRD) techniques, can be used to non-destructively and in situ evaluate die warpage and strain inside fully encapsulated chip packages. In this paper, we show that both synchrotron-based X-Ray Diffraction Imaging (...
Article
Full-text available
Transmission X-ray diffraction imaging in both monochromatic and white beam section mode has been used to measure quantitatively the displacement and warpage stress in encapsulated silicon devices. The displacement dependence with position on the die was found to agree well with that predicted from a simple model of warpage stress. For uQFN microco...
Article
A method is proposed to extract the electrical data for surface doping profiles of semiconductors in unison with the chemical profile acquired by secondary-ion mass spectrometry (SIMS)—a method we call SIMSAR (secondary-ion mass spectrometry and resistivity). The SIMSAR approach utilizes the inherent sputtering process of SIMS, combined with sequen...
Article
Full-text available
We present a low-cost fabrication procedure for the production of nanoscale periodic GaAs nanopillar arrays, using the nanosphere lithography technique as a templating mechanism and the electrochemical metal assisted etch process (MacEtch). The room-temperature photoluminescence (PL) and Raman spectroscopic properties of the fabricated pillars are...
Article
Full-text available
We describe an X-ray diffraction imaging technique for nondestructive, in situ measurement of die warpage in encapsulated chip packages at acquisition speeds approaching real time. The results were validated on a series of samples with known inbuilt convex die warpage, and the measurement of wafer bow was compared with the results obtained by optic...
Research
Full-text available
The asterism observed in white radiation X-ray diffraction images (topographs) of extended cracks in silicon is investigated and found to be associated with material that is close to breakout and surrounded by extensive cracking. It is a measure of the mechanical damage occurring when the fracture planes do not follow the low-index cleavage planes...
Article
Full-text available
The asterism observed in white radiation X-ray diffraction images (topographs) of extended cracks in silicon is investigated and found to be associated with material that is close to breakout and surrounded by extensive cracking. It is a measure of the mechanical damage occurring when the fracture planes do not follow the low-index cleavage planes...
Article
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We demonstrate the growth of multilayer and single layer graphene on copper foil using bipolar pulsed direct current (DC) magnetron sputtering of a graphite target in pure Ar atmosphere. Single layer and few layer graphene films (SG and FLG) are deposited at temperatures ranging from 700-920 °C in less than 30 minutes. We find that the deposition a...
Article
Full-text available
Next generation “More than Moore” integrated circuit (IC) technology will rely increasingly on the benefits attributable to advanced packaging (www.itrs.net [1]). In these increasingly heterogeneous systems, the individual semiconductor die is becoming much thinner (25 to 50 μm, typically) and multiple dies can be stacked upon each other. It is dif...
Article
Full-text available
The geometry of fracture associated with the propagation of cracks originating at the edges of (001) oriented, 200 mm diameter silicon wafers has been investigated under two regimes of high temperature processing. Under spike annealing, fracture did not occur on low index planes and all except one wafer exhibited crack patterns that started initial...
Article
Full-text available
The defect structure of HVPE-GaN crystals is examined using synchrotron white-beam X-ray topography (SWXRT) and topography results are interpreted and discussed in comparison to reciprocal lattice point broadening from high resolution X-ray diffraction (HRXRD) measurements. Two as-received commercial HVPE-GaN wafers from two different vendors and o...
Patent
Patent: Google Patent. Available online: https://www.google.com/patents/US20150204822
Article
Full-text available
Quantitative characterization of local strain in silicon wafers is critical in view of issues such as wafer handling during manufacturing and strain engineering. In this work, full-field X-ray microdiffraction imaging using synchrotron radiation is employed to investigate the long-range distribution of strain fields in silicon wafers induced by ind...
Article
Full-text available
Advanced More than Moore integrated circuit chip packaging is leading to the development of multiply stacked silicon die and these die are becoming ever thinner. This is leading to reliability problems. One of these is process induced die strain/warpage and there is no compelling metrology which can non-destructively measure the warpage of the die...
Article
For demanding GaN-based applications like laser diodes or high mobility transistors there is a need for substrate material with low defect densities, since threading dislocations act as centers of non-radiative recombination, increasing the leakage current, reducing the room temperature mobility and thereby limiting the efficiency, performance and...
Article
Full-text available
A reduction in the κ-value of dielectric materials is of great interest today as it leads to the reduction of resistance–capacitance delays and parasitic capacitances within integrated circuits, thereby improving device performance. We have recently reported our studies on the great potential of the Poly phenyl methyl silsesquioxane (PMSQ) low-κ fi...
Article
The effects of post-annealing conditions on solid-phase crystallization of atomic-layer-deposited HfO2 films grown on GaAs were investigated. Film properties, including crystallinity (preferential crystal orientation and crystallite size), thickness, density, permittivity, optical band gap and chemical composition were monitored as a function of an...
Article
Full-text available
p-type transparent conducting CuBr thin films were grown by thermal evaporation of CuBr followed by oxygen plasma treatment. Efficient incorporation of oxygen in to the CuBr films was revealed and the influence of plasma exposure on the electrical, structural, optical and electronic properties of CuBr films was investigated. X-ray diffraction (XRD)...
Technical Report
Full-text available
Similar to X-ray diffraction, Synchrotron X-ray Topography (SXRT) is also a non-destructive method that is ideal for studying high quality crystalline materials, and in particular it can image defects and strain fields distributed within the crystals. Using a white beam for SXRT brings several benefits, such as: sample orientation is not necessary,...
Conference Paper
Full-text available
Advanced packaging is a key 'More than Moore' (MtM) enabling technology [1]. In all of these advanced packaging processes the semiconductor die are becoming much thinner (e.g. 25-50 μm thick) and many packages include multiply stacked silicon die. This leads to very thin packages where there is a trade-off between the thickness of constituent packa...
Article
Hydroxyapatite (HA) coatings are widely applied to enhance the level of osteointegration onto orthopaedic implants. Atmospheric plasma spray (APS) is typically used for the deposition of these coatings, however HA crystalline changes regularly occur during this high thermal process. This paper reports on the evaluation of a novel low temperature (<...
Article
Full-text available
Reliability issues as a consequence of thermal/mechanical stresses created during packaging processes have been the main obstacle towards the realisation of high volume 3D Integrated Circuit (IC) integration technology for future microelectronics. However, there is no compelling laboratory-based metrology that can non-destructively measure or image...
Patent
A photoacoustic metrology tool comprises at least one light source for optically exciting a unit under test (UUT). A volume is provided for capturing acoustic energy emanating from the UUT as result of optical excitation thereof. An acoustic pick-up is provided for receiving the captured acoustic energy and generating a corresponding electrical sig...
Article
Full-text available
The behaviour of microcracks in silicon during thermal annealing has been studied using in situ X-ray diffraction imaging. Initial cracks are produced with an indenter at the edge of a conventional Si wafer, which was heated under temperature gradients to produce thermal stress. At temperatures where Si is still in the brittle regime, the strain ma...
Article
Full-text available
We report on a systematic investigation of the electronic properties of UV-light emitting Zn doped CuCl thin films implemented using near edge x-ray absorption fine structures (NEXAFS) and high-resolution x-ray photoemission spectroscopy. A clear shift of the valence band maximum towards higher binding energy by 0.2 ± 0.1 eV was observed in Zn dope...
Article
In this work we demonstrate simple techniques to form well crystallised CuAlO2 powders and thick films from CuO and boehmite or alumina, using a novel molten salt painting process. We examine the formation mechanism using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and in situ high temperature X-ray diffrac...
Article
Full-text available
Narure News & Views: A discussion of a new technique. A clever combination of existing techniques has produced three-dimensional atomic images of individual platinum nanoparticles, disclosing the atomic structure of crystal defects within them.
Article
Synchrotron X-Ray Topography (SXRT) has been performed on a germanium-silicon substrate fabricated by direct wafer bonding. SXRT allows for quantification of the stress at the bonded interface. This non-invasive techniques help assess the likelihood of defect nucleation induced by the bonding process. This study shows that the stress at the interfa...
Article
Full-text available
The apparatus for X-ray diffraction imaging (XRDI) of 450-mm wafers, is now placed at the ANKA synchrotron radiation source in Karlsruhe, is described in the context of the drive to inspect wafers for plastic deformation or mechanical damage. It is shown that full wafer maps at high resolution can be expected to take a few hours to record. However,...
Article
The evaluation of heat production from gold nanoparticles (AuNPs) irradiated with radiofrequency (RF) energy has been problematic due to Joule heating of their background ionic buffer suspensions. Insights into the physical heating mechanism of nanomaterials under RF excitations must be obtained if they are to have applications in fields such as na...
Article
The selection of appropriate characterization methodologies is vital for analyzing and comprehending the sources of defects and their influence on the properties of heteroepitaxially grown III–V layers. In this work, we investigate the structural properties of GaAs layers grown by metal-organic vapour phase epitaxy on Ge substrates—(1 0 0) with 6°...
Article
Full-text available
The evaluation of heat production from gold nanoparticles (AuNPs) irradiated with radio-frequency (RF) energy has been problematic due to Joule heating of their background ionic buffer suspensions. Insights into the physical heating mechanism of nanomaterials under RF excitations must be obtained if they are to have applications in fields such as n...
Conference Paper
Full-text available
Manufacturing-induced thermal stress created during the fabrication of packaged integrated circuits can potentially lead to device failure. Therefore, the need to develop metrologies that can be used to effectively measure stress/strain in systems-on-chip or systems-in-package is identified by the International Technology Roadmap for Semiconductors...